I mostly like to shoot landscapes or architecture, but I haven't explored portraits yet (so I don't know how much I could like them). Surely I don't like macros, fisheye stuff, weddings.

I was wondering what to do with my stuff... since I got the 15-85 (that on APS-C is exceptional) I've never used the Sigma 10-20, due to the better sharpness of the Canon. I thought about the new Sigma 8-16, that is sharper and wider than the 10-20. But... if I ever wanted to go full frame?

I was considering selling the 60D with 15-85 and 10-20, and getting a 6D that suits well my 70-200 and 50 prime. But then, I'd have to spend a lot of additional money for a good ultrawide full frame lens.